1. Field of the Invention
The invention is directed to a driving device, particularly for driving a hatch in a vehicle, with a first housing part that can be connected to a stationary base part or to a movable structural component part the movable structural component part or the stationary base part, a spindle drive by which the first housing part and second housing part are movable axially relative to one another, a rotary drive which drives the spindle drive in rotation that comprises a motor and a gear unit accommodated in a gear unit housing, and a braking device.
2. Description of the Related Art
Driving devices of the kind mentioned above are known in practice for opening and closing hatchbacks, trunk lids, engine hoods, and doors in motor vehicles. Both sides of the hatches are often driven electromechanically so that the hatches and hoods do not warp when swiveling open and closed.
Alternatively, drive systems are used that drive the hatches electromechanically in the opening and closing direction on only one side, while a gas spring is arranged on the other side of the hatch. This gas spring compensates for the weight force of the hatch and substantially reinforces only the opening of the hatch. An opening and closing system of this kind is better than the variant which is driven electromechanically on both sides and is therefore preferably installed in most applications.
However, drive systems which drive the hatches electromechanically in the opening and closing direction on only one side can also be used. DE 10 2007 029 591 A1 discloses a driving device whose holding-open force is increased by a centrifugal brake. The braking device is operative whenever the rotary drive is not in operation. However, there is also a need for driving devices in which the operation of the braking device depends upon the stroke.